When driving a vehicle, the driver needs to be aware of a variety of driver information when the vehicle is going at a high speed, so as to avoid accidents. Usually, the driver information is displayed on the dashboard of the vehicle. However, when the vehicle is going at a high speed, an accident may occurs because the driver needs to bow his/her head to check the driver information on the dashboard. Thus, many vehicles currently provide a head up display (HUD) mounted on the windscreen panel in the front of the vehicle to display the drive information, such as speed, gas consumption, navigation information, and around view, etc., so that the driver does not have to bow his/her head to see the important information for operating the vehicle and reduce the frequency of checking the dashboard, thereby preventing interruption of attention and loss control of situation awareness. By adopting the HUD technology for vehicles, driving security can be improved, and car accidents can be reduced. Thus, several advanced countries have been making efforts in the development of relevant fields.
When it comes to the current projection technology, the HUDs are categorized into “LED reflective” type and “LCD imaging” type. However, the two types of HUDs merely display the driver information with a single display screen, and is unable to provide a plurality of projection images having preferable aspect ratios and resolutions by using a single image source.